Currently, the most common hydrogen storage technologies include high-pressure gaseous storage, cryogenic liquid storage, and solid-state storage. Among these, high-pressure gaseous storage has emerged as the most mature technology due to its low cost, rapid hydrogen refueling, low energy consumption, and simple structure, making it the preferred hydrogen storage technology.
Four Types of Hydrogen Storage Tanks:
Apart from the emerging Type V full composite tanks without internal liners, four types of hydrogen storage tanks have entered the market:
1.Type I all-metal tanks: These tanks offer larger capacity at working pressures ranging from 17.5 to 20 MPa, with lower costs. They are used in limited quantities for CNG (compressed natural gas) trucks and buses.
2.Type II metal-lined composite tanks: These tanks combine metal liners (typically steel) with composite materials wound in a hoop direction. They provide relatively large capacity at working pressures between 26 and 30 MPa, with moderate costs. They are widely used for CNG vehicle applications.
3.Type III all-composite tanks: These tanks feature a smaller capacity at working pressures between 30 and 70 MPa, with metal liners (steel/aluminum) and higher costs. They find applications in lightweight hydrogen fuel cell vehicles.
4.Type IV plastic-lined composite tanks: These tanks offer smaller capacity at working pressures between 30 and 70 MPa, with liners made of materials such as polyamide (PA6), high-density polyethylene (HDPE), and polyester plastics (PET).
Advantages of Type IV Hydrogen Storage Tanks:
Currently, Type IV tanks are widely used in global markets, while Type III tanks still dominate the commercial hydrogen storage market.
It is well known that when hydrogen pressure exceeds 30 MPa, irreversible hydrogen embrittlement may occur, leading to corrosion of the metal liner and resulting in cracks and fractures. This situation can potentially lead to hydrogen leakage and subsequent explosion.
Additionally, aluminum metal and carbon fiber in the winding layer have a potential difference, making direct contact between the aluminum liner and carbon fiber winding susceptible to corrosion. To prevent this, researchers have added a discharge corrosion layer between the liner and winding layer. However, this increases the overall weight of the hydrogen storage tanks, adding to logistical difficulties and costs.
Secure Hydrogen Transportation: A Priority:
Compared to Type III tanks, Type IV hydrogen storage tanks offer significant advantages in terms of safety. Firstly, Type IV tanks utilize non-metallic liners composed of composite materials such as polyamide (PA6), high-density polyethylene (HDPE), and polyester plastics (PET). Polyamide (PA6) offers excellent tensile strength, impact resistance, and high melting temperature (up to 220℃). High-density polyethylene (HDPE) exhibits excellent heat resistance, environmental stress crack resistance, toughness, and impact resistance. With the reinforcement of these plastic composite materials, Type IV tanks demonstrate superior resistance to hydrogen embrittlement and corrosion, resulting in an extended service life and enhanced safety. Secondly, the lightweight nature of the plastic composite materials reduces the weight of the tanks, resulting in lower logistical costs.
Conclusion:
The integration of composite materials in Type IV hydrogen storage tanks represents a significant advancement in enhancing safety and performance. The adoption of non-metallic liners, such as polyamide (PA6), high-density polyethylene (HDPE), and polyester plastics (PET), provides improved resistance to hydrogen embrittlement and corrosion. Moreover, the lightweight characteristics of these plastic composite materials contribute to reduced weight and lower logistical costs. As Type IV tanks gain wide use in the markets and Type III tanks remain dominant, the continuous development of hydrogen storage technologies is crucial for realizing the full potential of hydrogen as a clean energy source.
Post time: Nov-17-2023